Michael Portillo begins the final leg of his railway journey, beginning in the harbour town of Dun Laoghaire. He joins a crew of geological surveyors to discover what lies beneath Dublin Bay.
In Sandycove, he meets James Joyce devotees in the town where he found inspiration. At New Ross, he sees a replica of a ship that toook emigrants to America during and after the Irish Famine.
At the Kennedy Homestead in Dunganstown, Michael meets JFK's great-great-great nephew, and at Rosslare, Michael discovers how business is booming in Ireland's closest ferry port to France.